A spontaneous self-reference effect in memory: why some birthdays are harder to remember than others

The self-reference effect in memory is defined as the memory advantage for materials that have been processed in relation to the self. Existing demonstrations of the self-reference effect rely on laboratory stimuli and use explicit cues to prompt self-relevant encoding. In three studies, we used participants' memories for birthdays to document a naturalistic case of the self-reference effect that did not depend on explicit self-cues. In Study 1, the birthdays that participants free-recalled were closer on average to their own birthday than would be expected by chance. In Study 2, participants were more likely to remember the birthday of a friend if the friend's birthday was close to their own, and they were more likely to forget the friend's birthday if it was distant. In Study 3, we demonstrated experimentally that the self-reference effect occurs for newly introduced individuals. Our findings suggest that the self-reference effect can occur spontaneously in the absence of explicit self-cues if the material to be learned automatically activates self-relevant information.